Control panels of this type are already known which comprise a body having a front panel, a printed circuit carried by the front panel, and a display device which is connected to the printed circuit and which is located behind a window formed through the front panel. Such a panel may for example be used for controlling an installation for heating and/or air conditioning the cabin of a motor vehicle.
The front panel of the control panel (or control unit) is conventionally incorporated in a substantially vertical position within the fascia or console of the motor vehicle, so that the display device can be visible to the driver. Conventionally again, the front panel contains a keypad consisting of a plurality of touch elements such as buttons or the like, which are arranged to be operated by the driver of the vehicle. The front panel generally contains lighting means for the purpose of illuminating the keypad and various symbols or pictorial displays, especially for use when driving at night. In addition, the front panel usually contains indicator lights such as light emitting diodes, which light up when the control unit is in operation.
Control units of the type just discussed are known in which the printed circuit comprises a single circuit board disposed parallel to the front panel. This arrangement has the disadvantage that it leaves too little space available to accommodate conveniently the electronic components and the connecting tracks associated with the printed circuit.
Control units of the same type are also known in which the printed circuit comprises two circuit boards arranged at right angles to each other, and also arranged to be able to be separated from each other or in contact with each other. This particular arrangement makes it necessary to make some kind of special provision for fastening the display device behind the front panel of the control unit. These fastening means may for example consist of a flexible connection between the display device and one of the circuit boards of the printed circuit, and this then makes it necessary to provide a connection between the two circuit boards.
The said means may also consist of a seal or lugs bearing on the display device, which then makes it necessary to provide a suitable flexible component such as a braid, consisting of connecting wires between the display device itself and one of the printed circuit boards.
All of these arrangements are costly and do not always enable correct retention of the display device in engagement behind the front panel to be guaranteed. As a result of this, vibrations can be set up, and a gap may appear at the perimeter of the display device.